1. Field of the Invention
The present invention is generally directed to the continuous testing of sealed, generally fluid-tight and flexible packages to determine whether or not such packages or seals thereof have defects, such as air leaks and the like. More specifically, it pertains to a novel and improved leak detecting method and apparatus which facilitates the rapid and accurate in-line leak testing of a plurality of continuously conveyed generally fluid-tight packages in a simple but yet reliable manner without destruction to the package or the contents in the package.
2. Brief Description of the Prior Art
In general, it is a rather conventional industrial practice to test sealed and enclosed packages, containers, or the like, in order to determine whether or not such packages or containers have defects such as leaks that might otherwise result in damage or loss of the contents within the package. Should the packages possess leaks they, of course, fail to adequately perform their intended function. In production line testing for leaks in sealed and generally fluid-tight packages, especially packages fabricated from a relatively flexible material, it is highly desirable that such testing be performed in a continuous manner which is not only dependable and provides economic savings in time, labor and costs, but one which does not otherwise damage the package or the contents within the package during the testing operation.
In the packaging field, there are several known types of mechanisms and methods which enable the testing of sealed and generally fluid-tight packages, containers, and the like. One such known leak detecting device, such as basically described in U.S. Pat. No. 3,396,842, essentially discloses an arrangement wherein the containers to be tested are conveyed along a path and a relatively heavy testing wheel serves to compress each of the containers passing thereunder to determine whether or not the container is properly pressurized. If a container has a leak or is not properly filled, it will be somewhat crushed under the load imposed by the testing wheel. Quite obviously, the foregoing described apparatus would not be particularly suitable in those circumstances, wherein relatively thin-walled, flexible containers housing somewhat easily damageable contents are to be tested. This is by virtue of the fact that a rather heavy testing wheel or the like would tend to crush each package as well as the contents thereof. Of course, such a testing technique would be especially unsuitable in situations wherein cigarette packages and the like are to be selectively tested for the presence of leaks in the package or seals thereof.
Other known approaches for use in detecting leaks in packages, especially fluid-tight packages, are essentially directed to arrangements which determine whether or not vacuum conditions in such packages have been lost. These known techniques, likewise as with the previously mentioned apparatus, are basically unsuitable for enabling the continuous, rapid, and accurate testing of packages. This is by reason of the fact that, in normal practice, the packages are placed within an evacuated chamber or the like and subjected to predetermined pressure conditions for a certain time interval. Consequently, it will be readily evident that such prior art techniques suffer from the shortcoming of having a continuous advancement of packages interrupted for the purposes of actually testing the package or the like. Accordingly, these types of prior art devices fail to provide suitable arrangements which enable the rapid and continuous leak detecting of a plurality of containers as such are continuously and successively advanced along a predetermined path.
Another known prior art approach for testing for leaks and the like basically operates on the traced gas principle, wherein sealed and enclosed packages and the like are compressed or otherwise pressurized so that should a leak exist it would be ascertained through the monitoring of the leaked trace gas. Such approach is similarly subject to the shortcoming of having the test conducted while the package is stationary and not continuously advancing.
As can be fully appreciated from the foregoing comments, known prior art apparatuses suffer from certain disadvantages in that they are not particularly adapted for use in rapidly and accurately testing for leaks on a production line basis, such that the packages to be tested are continuously advanced along a predetermined path without their advancement being subject to interruption, and in a manner whereby neither the package nor the contents of either the good or defective packages would be destroyed or otherwise adversely damaged. Additionally, such heretofore known prior art constructions have essentially failed to provide a production line testing and sorting apparatus of the above category which would enable the achievement of the foregoing in a simple fashion but yet in a highly reliable manner.
Accordingly, therefore, it is an object of the present invention to overcome the aforementioned disadvantages normally associated with conventional types of known prior art leak detecting methods and apparatuses.